OEM Exhaust

Greetings,
I am currently shopping for a 2018-21 JGC and noticed that the exhaust on one of the vehicles I am considering is different than all the others.
Seems like the std routing for 3.6L V6 is two pipes to the rear bumper with a resonator? on each pipe just ahead of the tip.
On the vehicle with different layout, the two pipes come back together and join into one resonator/muffler? that is in front of, and parallel to the rear bumper, then two seperate pipes route back out of the resonator to each side of the vehicle. Tips look the same and are in the same location, but vehicle only has one resonator/muffler in back instead of two like the others.
Anybody know why this would be different from the others? It's a California car... Could it be an aftermarket system? But it doesn't look like it is.... Looks factory..
Any insights appreciated.
-Arboh